ditty vs psalmody

ditty

noun
  • A short, simple verse or song. 

  • A saying or utterance, especially one that is short and frequently repeated. 

verb
  • To sing; to warble a little tune. 

psalmody

noun
  • The singing or the writing of psalms. 

  • A collection of psalms. 

verb
  • To celebrate in psalms. 

How often have the words ditty and psalmody occurred in a corpus of books? (source: Google Ngram Viewer )